Canadian researchers found almost one in 12 people had admitted engaging or initiating some sort of sexual activity while they slept.

Men accounted for three-quarters of the self-reported "sexsomniacs", they found.

Experts say such sexual behaviour that occurred while sleeping can range from masturbation through to physical intercourse.

In their study, presented at a recent sleep conference, researchers from the Sleep Research Laboratory at the University Health Network in Toronto, found the disorder was more common than previously thought.

In the study, which has not been published, researchers interviewed 832 patients who they suspected of suffering from some sort of sleep disorder.